Auxence Itoua Langa said Friday that individuals opened fire with automatic weapons on a group of gendarmes about 40 kilometers (25 miles) south of the capital, Brazzaville. He said several people died, but did not give a figure.

A police official, who spoke on condition of anonymity because he was not permitted to speak to media, said the conductor and two gendarmes died.

The army has been deployed in the region since April after attacks by former militiamen known as Ninjas Nsiloulou killed at least 17 people. Amnesty International said the military launched airstrikes then, killing 30.